Suitability of Gelatin Methacrylate and Hydroxyapatite Hydrogels for 3D-Bioprinted Bone Tissue.

BACKGROUND: Complex bone defects are challenging to treat. Autografting is the gold standard for regenerating bone defects; however, its limitations include donor-site morbidity and increased surgical complexity. Advancements in 3D bioprinting (3DBP) offer a promising alternative for viable bone grafts. In this experiment, gels composed of varying levels of gelatin methacrylate (GelMA) and hydroxyapatite (HA) and gelatin concentrations are explored. The objective was to increase the hydroxyapatite content and find the upper limit before the printability was compromised and determine its effect on the mechanical properties and cell viability. METHODS: Design of Experiments (DoE) was used to design 13 hydrogel bioinks of various GelMA/HA concentrations. These bioinks were assessed in terms of their pipettability and equilibrium modulus. An optimal bioink was designed using the DoE data to produce the greatest stiffness while still being pipettable. Three bioinks, one with the DoE-designed maximal stiffness, one with the experimentally defined maximal stiffness, and a literature-based control, were then printed using a 3D bioprinter and assessed for print fidelity. The resulting hydrogels were combined with human bone-marrow-derived mesenchymal stromal cells (hMSCs) and evaluated for cell viability. RESULTS: The DoE ANOVA analysis indicated that the augmented three-level factorial design model used was a good fit (p < 0.0001). Using the model, DoE correctly predicted that a composite hydrogel consisting of 12.3% GelMA, 15.7% HA, and 2% gelatin would produce the maximum equilibrium modulus while still being pipettable. The hydrogel with the most optimal print fidelity was 10% GelMA, 2% HA, and 5% gelatin. There were no significant differences in the cell viability within the hydrogels from day 2 to day 7 (p > 0.05). There was, however, a significantly lower cell viability in the gel composed of 12.3% GelMA, 15.7% HA, and 2% gelatin compared to the other gels with a lower HA concentration (p < 0.05), showing that a higher HA content or print pressure may be cytotoxic within hydrogels. CONCLUSIONS: Extrusion-based 3DBP offers significant advantages for bone-tissue implants due to its high customizability. This study demonstrates that it is possible to create printable bone-like grafts from GelMA and HA with an increased HA content, favorable mechanical properties (145 kPa), and a greater than 80% cell viability.

A Recalcitrant Case of Senear-Usher Syndrome Treated With Rituximab.

A 51-year-old uninsured, otherwise healthy male who works in the fishing industry presented with a two-month history of pruritic scaly plaques on his face, scalp, and trunk and mild photosensitivity. A biopsy of a scalp lesion revealed acantholysis consistent with pemphigus foliaceus. Laboratory testing demonstrated elevated anti-desmoglein 1, positive antinuclear antibodies (ANA and anti-dsDNA), and elevated Sjögren's anti-SS-A antibodies. The patient was diagnosed with pemphigus erythematosus. The patient was not optimally responsive and was unable to discontinue systemic corticosteroids despite a maximum dosage of mycophenolate mofetil of 3000 mg/day. Hence, rituximab was added as a rescue treatment with the rheumatoid arthritis protocol. Three months after starting rituximab, there was a marked improvement in symptoms with complete resolution of cutaneous lesions.

Treatment of Esophageal Perforation: Endoscopic Vacuum-Assisted Closure.

Surgical repair of type C esophageal atresia (EA) with distal tracheoesophageal fistula (TEF) is complicated by an anastomotic leak in 10%-30% of cases with associated morbidity. A novel procedure in the pediatric population, endoscopic vacuum-assisted closure (EVAC), accelerates the healing of esophageal leaks by using the effects of VAC therapy, including fluid removal and stimulation of granulation tissue formation. We report 2 additional cases of chronic esophageal leak treated with EVAC in EA patients. The first is a patient with a previously repaired type C EA/TEF and left congenital diaphragmatic hernia complicated by an infected diaphragmatic hernia patch erosion into the esophagus and colon. Additionally, we discuss a second case using EVAC for early anastomotic leak following type C EA/TEF repair in a patient who was later found to have a distal congenital esophageal stricture.

EFFECTS OF MOUTHING AND INTERLOCUTOR PRESENCE ON MOVEMENTS OF VISIBLE VS. NON-VISIBLE ARTICULATORS.

Speakers take into account what information a conversation partner requires in a given context in order to best understand an utterance. Despite growing evidence showing that movements of visible articulators such as the lips are augmented in mouthed speech relative to vocalized speech, little to date has been done comparing this effect in visible vs. non-visible articulators. In addition, no studies have examined whether interlocutor engagement differentially impacts these. Building on a basic present/not-present design, we investigated whether presence of audible speech information and/or an interlocutor affect the movements of the lips and the tongue. Participants were asked to a) speak or b) mouth three target syllables in interlocutor-present and interlocutor-not-present conditions, while lip and tongue movements were recorded using video and ultrasound imaging. Results show that lip protrusion was greater in mouthed conditions compared to vocalized ones and tongue movements were either attenuated (/wa/) or unaffected (/ri/, /ra/) by these same conditions, indicating differential effects for the visible and non-visible articulators in the absence of an auditory signal. A significant interaction between the social engagement and vocalizing conditions in reference to lip aperture showed that participants produced smaller lip apertures when vocalizing alone, as compared to when in the presence of an interlocutor. However, measures of lip protrusion failed to find an effect of social engagement. We conclude that speakers make use of both auditory and visual modalities in the presence of an interlocutor, and that when acoustic information is unavailable, compensatory increases are made in the visual domain. Our findings shed new light on the multimodal nature of speech, and pose new questions about differential adaptations made by visible and non-visible articulators in different speech conditions.

Les locuteurs prennent en compte l'information qu'un partenaire de conversation nécessite pour mieux comprendre une expression. Malgré l'évidence grandissante que les mouvements d'articulateurs visibles (comme les lèvres) sont augmentés dans l'articulation silencieuse par rapport à l'articulation vocalisée, peux d'études ont comparé cet effet dans les articulateurs visibles contre les articulateurs non visibles. De plus, aucune étude n'a examiné si l'engagement de l'interlocuteur changera ces résultats. En élaborant un conception d'expérience présent/non présent, nous avons testé si la présence d'information audible et/ou d'un interlocuteur affecte les mouvements des lèvres et de la langue. Les participants ont parlé trois syllabes, avec et sans production audible, dans chacune des conditions interlocuteur-présent et interlocuteur-non présent. Les mouvements des lèvres et de la langue étaient enregistrés avec la vidéo et l'échographie. Nos résultats montrent que la protubérance des lèvres était plus grande dans les conditions non audibles par rapport à ceux audibles et que les mouvements de la langue étaient atténués (/wa/) ou non affectés (/ri/, /ra/) par ces mêmes conditions, indiquant les effets différents pour les articulateurs visibles et non-visibles dans l'absence d'un signal auditif. Une interaction significative entre les conditions d'engagement sociale et d'audibilité de vocalisation avec référence à la fermeture orale a montré que les participants ont produit des fermetures plus étroites dans les conditions de vocalisation audible, interlocuteur-non présent (par rapport à la condition interlocuteur-présent). Cependant, les mesures de protubérance des lèvres n'étaient pas affectées par condition d'engagement sociale. Nous concluons que les locuteurs utilisent à la fois les modalités auditives et visuelles dans la présence d'un interlocuteur, et lorsque l'information acoustique n'est pas disponible, les augmentations compensatoires sont réalisés dans le domain visuel. Nos résultats soulignent encore le caractère multimodal de discours, et posent des nouvelles questions au sujet des adaptations différentielles faites par les articulateurs visibles et non visibles dans les différentes conditions de parole.

An "ecological" action-based synthesis.

We expand upon Morsella et al.'s synthesis in the direction of what Gibson (1979) called an ecological approach to perception. Morsella et al. describe consciousness as a director of voluntary action, but they understate the role of the environment in its evolution as well as in directing behavior. We elaborate these roles in the context of the concept of affordances.

Determination of vitamins A (retinol) and E (alpha-tocopherol) in foods by liquid chromatography: collaborative study.

A collaborative study was conducted for the determination of vitamins A and E. Existing AOAC liquid chromatographic (LC) methods are suited for specific vitamins A and E analytical applications. This method differs from existing methods in that it can be used to assay samples in all 9 sectors of the food matrix. Standards and test samples are saponified in basic ethanol-water solution, neutralized, and diluted, converting fats to fatty acids and retinol esters and tocopherol esters to retinol and tocopherol, respectively. Retinol and alpha-tocopherol are quantitated on separate LC systems, using UV detection at 313 or 328 nm for retinol, and fluorescence detection (excitation 290 nm, emission 330 nm) for alpha-tocopherol. Vitamin concentrations are calculated by comparison of the peak heights or peak areas of vitamins in test samples with those of standards.